133 lines
5.2 KiB
JavaScript
133 lines
5.2 KiB
JavaScript
/*
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* MIT License http://opensource.org/licenses/MIT
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* Author: Ben Holloway @bholloway
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*/
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'use strict';
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const os = require('os');
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const path = require('path');
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const postcss = require('postcss');
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const fileProtocol = require('../file-protocol');
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const algerbra = require('../position-algerbra');
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const ORPHAN_CR_REGEX = /\r(?!\n)(.|\n)?/g;
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/**
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* Process the given CSS content into reworked CSS content.
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*
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* @param {string} sourceFile The absolute path of the file being processed
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* @param {string} sourceContent CSS content without source-map
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* @param {{outputSourceMap: boolean, transformDeclaration:function, absSourceMap:object,
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* sourceMapConsumer:object, removeCR:boolean}} params Named parameters
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* @return {{content: string, map: object}} Reworked CSS and optional source-map
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*/
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function process(sourceFile, sourceContent, params) {
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// #107 libsass emits orphan CR not considered newline, postcss does consider newline (content vs source-map mismatch)
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const correctedContent = params.removeCR && (os.EOL !== '\r') ?
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sourceContent.replace(ORPHAN_CR_REGEX, ' $1') :
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sourceContent;
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// IMPORTANT - prepend file protocol to all sources to avoid problems with source map
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const plugin = Object.assign(
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() => ({
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postcssPlugin: 'postcss-resolve-url',
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prepare: () => {
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const visited = new Set();
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/**
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* Given an apparent position find the directory of the original file.
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*
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* @param startPosApparent {{line: number, column: number}}
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* @returns {false|string} Directory of original file or false on invalid
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*/
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const positionToOriginalDirectory = (startPosApparent) => {
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// reverse the original source-map to find the original source file before transpilation
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const startPosOriginal =
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!!params.sourceMapConsumer &&
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params.sourceMapConsumer.originalPositionFor(startPosApparent);
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// we require a valid directory for the specified file
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const directory =
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!!startPosOriginal &&
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!!startPosOriginal.source &&
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fileProtocol.remove(path.dirname(startPosOriginal.source));
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return directory;
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};
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return {
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Declaration: (declaration) => {
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var prefix,
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isValid = declaration.value && (declaration.value.indexOf('url') >= 0) && !visited.has(declaration);
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if (isValid) {
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prefix = declaration.prop + declaration.raws.between;
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declaration.value = params.transformDeclaration(declaration.value, getPathsAtChar);
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visited.add(declaration);
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}
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/**
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* Create a hash of base path strings.
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*
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* Position in the declaration is supported by postcss at the position of the url() statement.
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*
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* @param {number} index Index in the declaration value at which to evaluate
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* @throws Error on invalid source map
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* @returns {{subString:string, value:string, property:string, selector:string}} Hash of base path strings
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*/
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function getPathsAtChar(index) {
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var subString = declaration.value.slice(0, index),
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posSelector = algerbra.sanitise(declaration.parent.source.start),
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posProperty = algerbra.sanitise(declaration.source.start),
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posValue = algerbra.add([posProperty, algerbra.strToOffset(prefix)]),
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posSubString = algerbra.add([posValue, algerbra.strToOffset(subString)]);
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var result = {
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subString: positionToOriginalDirectory(posSubString),
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value : positionToOriginalDirectory(posValue),
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property : positionToOriginalDirectory(posProperty),
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selector : positionToOriginalDirectory(posSelector)
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};
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var isValid = [result.subString, result.value, result.property, result.selector].every(Boolean);
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if (isValid) {
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return result;
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}
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else if (params.sourceMapConsumer) {
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throw new Error(
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'source-map information is not available at url() declaration ' + (
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ORPHAN_CR_REGEX.test(sourceContent) ?
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'(found orphan CR, try removeCR option)' :
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'(no orphan CR found)'
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)
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);
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} else {
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throw new Error('a valid source-map is not present (ensure preceding loaders output a source-map)');
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}
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}
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}
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};
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}
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}),
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{ postcss: true }
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);
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// IMPORTANT - prepend file protocol to all sources to avoid problems with source map
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return postcss([plugin])
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.process(correctedContent, {
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from: fileProtocol.prepend(sourceFile),
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map : params.outputSourceMap && {
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prev : !!params.absSourceMap && fileProtocol.prepend(params.absSourceMap),
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inline : false,
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annotation : false,
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sourcesContent: true // #98 sourcesContent missing from output map
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}
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})
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.then(({css, map}) => ({
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content: css,
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map : params.outputSourceMap ? fileProtocol.remove(map.toJSON()) : null
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}));
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}
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module.exports = process;
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